Self-cleaning pressure filter systems are known. In systems of this kind available from Cellier America of Albany, N.Y., liquid to be filtered enters the interior of a circular cross section, cylindrical filter element, is filtered by passing radially outward through the perforate wall of the filter element and exits as a filtered liquid from the housing containing the filter element. A rotary cleaning unit orbits a longitudinally extending wiper circumferentially along the inner face of the filter element for the purpose of reducing the build-up of filtered-out solids on the inner face of the filter element. In each orbit, the orbiting wiper scrapes over a longitudinally extending, axially tensioned wire within the filter element, for the purpose of scraping solids from the wiper. The purpose is to reduce the amount of backwashing required to maintain filtering efficiency, and thereby to reduce the percentage of down time of the filter system.
However, the present Applicant has noted that prior filter systems of this kind may have unique cleaning problems of their own and that room for further improvement remains. The present invention is intended to overcome these problems.
Accordingly, the objects and purposes of the present invention include provision of a self-cleaning filter system in which a cleaning element movable along the unfiltered liquid side of the filter element cleans filtered-out solids therefrom, in which the cleaning element itself is subject to cleaning of solids accumulated thereon, in which cleaning of the filter element and cleaning element can proceed during filtration, in which several cleaning elements are alternatively located to clean the filter element, in which the buildup of filtered-out solids is minimized both on the filter element and on the cleaning element, in which the filter element may be cleaned by both doctoring and wiping actions, in which a given cleaning element is indexable to different positions with respect to the opposed face of the filter element as it is moved therealong, in which the filter element and cleaning element are readily removed from the filter housing for repair or replacement, and in which the cleaning apparatus can be constructed at relatively low cost from commonly available materials without special tools.
Further objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following description and inspecting the accompanying drawings.